N. F. A. Zainal

Miscibility and Conductivities of PEO/PMMA-LiClO4 Solid Polymer Electrolyte

Thin films of poly (ethylene oxide) (PEO), poly (methyl methacrylate) (PMMA) and selected blends of PEO/PMMA with and without the addition of LiClO4 were prepared using solution casting technique. The presence of a single Tg which corresponds closely to that of the Gordon Taylor equation confirms the miscibility of both the salt-free and salt-doped blends. The Tgs and the ion conductivity (σ) at room temperature of PEO, PMMA and the PEO/PMMA blends generally increase with ascending salt concentration (Y). Variations in the σ value as a function of Y for all the three systems correlate closely with their respective Tg results. PMMA-salt complex records the lowest σ value at all salt concentrations. PEO/PMMA/LiClO4 blend with 75 wt% PEO exhibits the highest σ value of 5 x 10-7 S cm-1 at Y = 0.10. The σ value of the blend-salt system is observed to be slightly lower than that of the PEO-salt system. This is due to reduced segmental motion cause by increased Tg of the blend and a decrease in free ions in the amorphous phase of PEO as a small amount of the salt is solvated by PMMA in the blend. Therefore, the percolation path lies in the amorphous PEO rich phase of the blend.

Growth Mechanism Of Carbon Nanotubes Prepared By Fluidized Floating Catalyst Method

In this paper, carbon nanotubes were synthesized by fluidized floating catalyst method which yielded high yield even at low temperature; 650° C using camphor oil as carbon source and Argon as carrier gas. Optimum concentration for trimetal alloy catalyst; Fe/Ni/Mg has been found to be the suitable catalyst for producing carbon nanotubes at high yield. Carbon nanotubes are formed by the evaporation of the camphor oil (precursor), which decomposes ‘in situ’ and aggregates on the metal alloy catalyst particles present in the ceramic boat. The morphology of carbon nanotubes were characterized by field emission scanning electron microscopy (FESEM). This result demonstrates that fluidized floating catalyst method is suitable for effective formation of CNTs with average size ∼11.5 nm. The morphological studies support ‘tip growth mechanism’ for the growth of the CNT’s in our case.

Optimization of Fe/Ni/Mg Trimetallic Catalyst for Carbon Nanotubes Growth by Using Fluidized Floating Catalyst Method

Fluidized floating catalyst method has been used for preparing carbon nanotubes with average size ∼11 nm which yielded high yield even at low temperature; 650° C. Optimum concentration of the Fe/Ni/Mg metal alloy catalyst has been found to be at 2.133% for producing carbon nanotubes with high yield. Carbon nanotubes are formed by the evaporation of the camphor oil (precursor), which decomposes ‘in situ’ and aggregates on the metal alloy catalyst particles present in the ceramic boat. From the PXRD analyses, graphite layers detected which provide an indication of the degree of graphitic character. However, by using the Scherrer equation is not suitable for carbon nanotubes as the value is slightly different from the average diameter determine from FESEM micrographs. Since the metallic alloy was obtained by calcining the respective nitrates, it is expected to have residual entrapped nitrogen, which may bond with the depositing CNTs as observed from FTIR spectroscopy.

Floating Catalyst Method for Preparation of Carbon Nanotubes Using Fe/Co/Al Catalyst by Thermal-CVD

Carbon nanotubes (Cnts) produced using single furnace thermal CVD method by the floating catalyst method, at low temperature condition; 650oC. Carbon nanotubes were produced from natural source of camphor oil, using Fe/Co/Al as catalyst source, yielding a thickened submicron vapor grown of multi-wall Cnts. Carbon nanotubes are observed to form by different weight composition of catalyst. For the production of carbon nanotubes, natural precursor was used as the carbon feedstock, and the catalysts were added in a precursor compound. FESEM analysis confirms that this type of stacked-cup Cnts is produced by vaporize catalyst and mixing with the hydrocarbon source. In fact, few Cnts have either a particle tip at the end or trapped metal particle inside the wide hollow core of this type of produced carbon material. Chemical properties carried out by FTIR and Raman spectroscopy.

The Electrical and Optical Properties of PMMA/MWCNTs Nanocomposite Thin Films

The poly(methyl methacrylate) (PMMA)/multi‐walled carbon nanotubes (MWCNTs) nanocomposite thin films have been prepared by spin‐coating technique. The electrical properties as well as UV‐Visible spectrophotometer have been studied as a function of the MWCNTs’ weight percentage. The electrical conductivity of the films increases by several orders of magnitude upon the addition of MWCNTs into PMMA solution. It was observed that the conductivity enhancement is interpreted by the formation of a continuous electron paths or conducting network in the polymer nanocomposite indicated by the efficient dispersion of MWCNTs into PMMA. The optical band gap of the films was assessed using Tauc approximation from the UV‐Vis spectra. The surface morphology was investigated using the scanning electron microscope (SEM) to study on the MWCNTs’ dispersion in the polymer matrix.

Properties Of Carbon Nanotubes Produced Using Fe/Co/Al Trimetallic Catalyst In Fluidized Floating Catalyst Method

Carbon nanotubes (CNTs) were synthesized by fluidized floating catalyst method by using camphor oil as the carbon source and Fe/Co/Al as the catalyst. The catalyst was prepared by sol‐gel method using nitrate salt. Carbon nanotubes were produced by using fluidized floating catalyst method, in low temperature condition; 650° C. The results showed that a thickened submicron vapor grown of multi‐wall nanotubes that produced only with a vaporize catalyst and the hydrocarbon source with diameters of about ∼30 nm. In fact, very few carbon nanotubes have either a particle tip at the end or trapped metal particle inside the wide hollow core of this type of produced carbon material. Structural characterizations have been done by FESEM, FTIR and XRD analyses.

Effect of CNTs in the Polymer Base Nano‐Composite Thin Films on the Structure and Electrical Properties

CNTs have been intensively investigated due to their unique, excellent properties of mechanical strength, chemical reactivity, electrical conductivity and also it unique structure. In this paper, we study the effect of CNTs in the polymer base nanocomposite thin film on structure properties. Poly [2‐methoxy, 5‐(2_‐ethyl‐hexyloxy)‐1, 4‐phenylenevinylene] (MEH‐PPV) was used as a polymer base nanocomposite thin film. Certain amounts of CNTs were added to MEH‐PPV for a different weight ratio to form nanocomposite thin films. Spin coating method was used to prepare the composite thin film of CNTs/MEH‐PPV. This MEH‐PPV/CNTs nanocomposite thin films structure was investigated by using Scanning Electron Microscope (SEM). The electrical conductivity was measured using 2‐point current‐voltage measurement and the value increased by several orders of magnitude upon the addition of CNTs into MEH‐PPV.

Efficient Synthesis of Carbon Nanotubes over Zeolites By Thermal Chemical Vapor Deposition

Properties of the influence on the zeolite as the support towards the starting carbon materials by using thermal chemical vapor deposition (Thermal‐CVD) to produced carbon nanotubes (CNTs) are investigated. The CNTs derived from camphor oil (C10H16O), a botanical hydrocarbon, has been found to be a promising precursor of carbon nanotubes (CNTs). Multi‐wall CNTs have been grown from simple pyrolysis of camphor oil in the temperature 650 °C in argon atmosphere at normal pressure using zeolite as a supported on Fe/Ni/Mn catalyst. On the other hand, multi‐wall nanotubes of uniform diameter (∼20–30 nm) could be produced with a yield as high as 90%. Structural characterizations have been done by FESEM, and FTIR analyses. Good crystallinity, high purity, and absence of amorphous carbon and metallic particles are the essential features of camphor oil‐grown nanotubes; which indirectly may be cost effective. The major parameters are also evaluated in order to obtain high‐yield and high‐quality CNTs.

Effect of epoxidation level on thermal properties and ionic conductivity of epoxidized natural rubber solid polymer nanocomposite electrolytes

Effect of epoxide content on the thermal and conductivity properties of epoxidized natural rubber (ENR) solid polymer nanocomposite electrolytes was investigated. Commercial available epoxidized natural rubber having 25 (ENR25) and 50 mole% (ENR50) epoxide, respectively were incorporated with lithium perchlorate (LiClO4) salt and titanium dioxide (TiO2) nanofiller via solution casting method. The solid polymer nanocomposite electrolytes were characterized by differential scanning calorimetry (DSC) and impedance spectroscopy (IS) for their thermal properties and conductivity, respectively. It was evident that introduction of LiClO4 causes a greater increase in glass transition temperature (Tg) and ionic conductivity of ENR50 as compared to ENR25. Upon addition of TiO2 in ENR/LiClO4 system, a remarkable Tg elevation was observed for both ENRs where ENR50 reveals a more pronounced changes. It is interesting to note that they exhibit different phenomenon in ionic conductivity with TiO2 loading where ENR25 sho...

Multi-Walled Carbon Nanotubes by Thermal-CVD Utilizing Palm DHSA as a Precursor

We illustrated the optimization of the growth of multi-wall carbon nanotubes (MWCNTs) using thermal chemical vapor deposition (CVD). Palm-based dihydrostearic acid (DHSA) which was never been reported as a precursor, was used as the precursor over five different trimetallic catalysts for the growth of MWCNTs. These trimetallic catalysts were prepared by sol-gel method and used to study on the effect of the production of the MWCNTs from palm DHSA. With different catalyst, the characteristics of MWCNTs changes such as diameter and crystallinity which was confirmed by SEM and Raman spectroscopy studies. The trimetallic catalysts give high yield and offer good graphitization of MWCNTs produced from palm DHSA.